This research program will develop a computerized assessment system and clinical test battery and evaluate the predictive validity of that test battery for diagnosis and determining medication levels for attention deficit hyperactivity disorder (ADHD) children. Seven laboratory and three ecologically based tests will be developed including a learning task (nonsense spelling), attention tasks (laboratory vigilance, attention switching, memory scanning), impulsivity tasks (motor stopping, draw a line, response perseveration), and ecologically based tasks attention and learning in a simulated classroom, attention in a simulated social recreational setting, distractibility during simulated homework). The station will include auditory/speech, response box and pen input/output control, video tape control and gaze direction and heart rate monitoring. The specific objectives include: 1) develop prototype test station, including specialized hardware for gaze and heart rate monitoring; 2) develop a clinical assessment battery of 10 tests; 3) determine ease of use of the test battery by ADHD technicians; 4) determine test/retest reliability and medication sensitivity of the tests; 5) correlate test battery results with behavioral and clinical measures obtained in the ADHD treatment training program; and 6) evaluate preliminary information regarding the utility of the utility of the measures in differentiating ADHD from normal children and medication levels.